“Amber-hunting?” Vi and I say together.

“Ah, maybe you don’t know,” says the beachcomber, waving her purple light about. “Amber glows under ultraviolet light. It’s hard to spot in the daytime, but at night it shines out a treat when I flash my UV torch on it. Look!”

And she pulls a handful of something out of her coat pocket and shines the purple light down onto it. We huddle round. There, in her palm, are several small stones, glowing faintly green in the ultraviolet.

“It’s the best time of the year for finding it,” she says, clutching her hats against the wind. “Ancient tree sap, as I’m sure you know. I once found a piece with a millipede in it, as big as your —”

“Mrs Fossil,” I say, jumping in before the story starts. “We’d love to see that. Maybe we can come tomorrow. But right now, we’re wondering if you have seen anyone else out here. On the beach. Someone heading for the wreck of the Leviathan perhaps.”

“For the wreck?” says Mrs F. “Surely no one would be that stupid. The tide may be low now, but it’ll rise again like a flood. Anyone foolish enough to be in that old wreck would be drowned in a jiffy.”

“Thanks,” I say. I manage to catch Violet’s eye despite the dark, and I realize that our vision is adapting after all.

“Aren’t you scared, Mrs Fossil?” says Vi. “To be out here in the dark, I mean? After what happened to you.”

I can just make out Mrs F’s topmost hat shaking from side to side.

“The way I see it, I was unlucky to get bitten last time. As long as I steer clear of rock pools, I reckon I’ll be fine. And I can’t resist these little beauties!” She waves her palmful of gems at us again.

“Even so,” says Violet. “Maybe you should call it a night. You’ve got some great amber there. Wouldn’t you like to go back to your wonderful shop and put the kettle on?”

“That sounds like a splendid idea!” Mrs F’s teeth flash purple-white in the UV light. “Would you two like to join me? I have scones.”

“We’d love to, but there’s something we have to do first,” I say, steering Violet away. “Goodnight, Mrs F!”

“Wait, I’m not sure I should leave you here,” Mrs Fossil calls hesitantly from behind us. “Why are you out on the beach, Herbie? In the dark?”

“It’s just lost-luggage business,” I call back. “Herbie Lemon and Violet Parma are on the case, if you see what I mean, ha ha!”

And we disappear into the night.

“Wait!” comes the fading voice of Mrs Fossil. “Wait, what did you say? Parma? Did you say Violet Parma?”